PRINCIPLES OF VETERINARY SURGERY 275 



gradual destruction of the micro-organisms, they should 

 be left to dry on the surface into the form of a scab. 



IV. PROTECTION AND AFTER-CARE.— Wounds 

 of animals must be protected, not only against infection, 

 but also against mechanical violence and motion. The pro- 

 tection against infection is no more important than the 

 others. As mentioned in a preceding paragraph, Lister em- 

 phasized too strongly the necessity of post-operative pro- 

 tection. It was then thought that an absolutely impervious 

 wrap was necessary to prevent invasion of poisons into the 

 wound. Strictly air-tight wraps and layer after layer of 

 antiseptic fabrics were placed over the trauma. Now, that 

 the behavior of micro-organisms is better understood, the 

 protective covering is known to be efifectual if it will pre- 

 vent dirt and dust from permeating through it. When a 

 wound is secreting freely the bandage may even be harmful 

 by spreading discharges over the surrounding surface and 

 by preventing their free outward flow. Protecting wraps 

 should be aseptic, or better still antiseptic, and they should 

 neither obstruct drainage nor impede the free circulation of 

 the blood to the part. 



For incised, aseptic, surgical wounds a liberal dusting 

 with boric acid covered over, first with absorbent cotton, 

 and then with a muslin bandage, constitutes a perfectly safe 

 dressing. Such a dressing may be left in place for six or 

 seven days without renewal, or it may be renewed every 

 day providing the wound itself is not disturbed. The daily 

 dressing of such wounds should consist simply of renewing 

 the boric acid and the re-adjusting the bandage, which is 

 very liable to become uncomfortable by pressing too taut 

 at dififerent points. This recourse is advisable, because the 

 first signs of sepsis are then noticed. The recommendation 

 to allow such wounds in animals to remain under cover until 

 the union is complete is not an absolutely safe one, because 



